I'll answer my own question
After further research it seems my usb to dvi converter was the one that supports lower resolutions (many say 1600x1200, but it still support 1920x1080). I bought another version which supported up to 2048x1152. I used the latest driver version (1.7, not beta) and it just worked!
So apparently the first version didn't use the latest chip but the new version did.